Automatic or semi-automatic single-serve coffee and/or espresso coffee machines become more and more popular. The main advantages of these single-serve coffee machines are, compared to fully automatic coffee machines (bean to cup coffee machines), their reduced complexity as well as their more hygienic usage. Due to their reduced complexity compared to fully automatic coffee machines, such single-serve coffee machines may be offered to the consumer at comparatively affordable prices. Single-serve coffee machines are also easy in handling for the consumer. Furthermore, both the time needed to brew coffee is reduced and the brewing process is simplified by eliminating the need to measure out portions, flavourings, and additives from large bulk containers.
Single-serve coffee machines rely on the basic principle to extract the coffee from grinded coffee or coffee powder that is encapsulated within a pad or capsule. These pads or capsules are inserted into a sealed brewing chamber of a brewing unit of the machine. After that, hot or cold water is injected or diffused into the brewing chamber and into the pad or capsule, so that coffee may be extracted therefrom. The used pads or capsules may then be thrown away. Depending on the ingredients enclosed within the pads or capsules, different types of coffee and/or espresso coffee recipes and flavours may be dispensed. It is even possible to extract tea, hot chocolate, soups or other types of hot or cold beverages with these types of single-serve machines. Therefore, these machines are herein generally denoted as beverage machines.
An example of such a machine is sold by the applicant under the name Senseo. This type of machine uses soft pads in which the extractable food product is enclosed. These soft pads are sometimes also denoted as pods.
However, other suppliers of single-serve coffee machines make use of differently shaped or sized coffee pads or differently shaped and sized capsules. These differently sized and shaped pads and capsules do not only require different receptacles within the coffee machine that are exclusively adapted to the shape and size of the specific pad or capsule. The different machine types also differ from a technical point of view. Machines using capsules usually use higher pressures (around 5 to 19 bar) than machines using the bigger and softer pads, like the Senseo machine which uses pressures of around 1.2 to 1.9 bar. The technical design of the brewing unit therefore differs for these different machine types significantly.
When someone would like to use different types of pads or capsules, different types of appliances are needed. This would mean different machines each with its specific way of working and consuming space in the kitchen.
WO 2013/079814 A1 and US 2013/0133522 A1 refer to single-serve coffee machines that allow using differently sized and shaped pads and capsules. Comparatively complicated adapters are used therein, one for each different type of pad or capsule. These adapters are relatively uncomfortable in handling. The adapters usually comprise a plurality of different parts that have to be assembled together in a correct manner by the consumer each time a new capsule or pad is inserted into one of the different adapters. Apart from that, a correctly balanced force distribution within the brewing unit and a proper sealing of the brewing chamber is still hard to guarantee.
A further problem that arises for combined pad and capsule machines is the fact that the liquid flow behaves fairly different in a pad than in a capsule. Capsules usually comprise a plastic or metallic main body that is covered at its top with a thin foil. It has been shown that the flow behaviour and the resulting coffee quality is improved if the liquid is injected into the capsule at its bottom side and leaves the capsule at its top through the foil. For combined pad and capsule machines, where the liquid is usually injected into the brewing chamber from the top, this would however mean that the capsule has to be inserted into the brewing unit upside-down. Even though this is technically feasible, it is less intuitive for the consumer to insert the capsule upside-down.
Thus, there is still room for improvement.